Ghost Gust

Posted March 2009

Due to some really cruddy weather in the Seattle area, this was the
first decent weekend since the middle of February. I went up to check
things out.

Winds were pretty light, about 4 knots or less in a ~45 degree
crosswind from the right. Still some ugly weather around, though, the
mountains ~20 miles east were obscured by clouds and rain. Bad weather
was forecasted to come back in four hours or so.

Zipped around for a bit, then returned home for some touch-and-goes.
First one was OK. Winds were still light...the "Super Unicom" was even
calling it calm, at one point.

Guy was shooting pictures in a Cessna about a half-mile from the
approach end, so I wrapped the next base leg in tight. I overshot the
turn to final a bit...strange, with no wind. Got it straightened out,
crossed the threshold, and the plane started to sag down.

I sucked back the stick a bit (still scads of airspeed) but we
ballooned up and yawed left a bit.

My usual practice when this happens is to goose the throttle a bit,
stabilize, then ease it down again. But something, SOMEthing didn't
feel right. Just did not have a good feeling for what was going one. So
I went to full power and started a go-around.

About a hundred feet up, it felt like I got hit with a snowball. The
plane skidded to the right and yawed left. The whole "sound quality"
changed; normally the sounds I hear are directly related to the
airspeed and throttle setting, but this sounded just like a gust
blowing over me when I was standing still.

It was all over in the blink of an eye.

The rest of the pattern was normal. I made the next circuit a full-stop
one (no fool I). On final, I noted that the wind sock was now standing
about 90 degrees to the runway, and almost completely extended. No
gusts, this time, just a normal wing-low landing and roll out.

Strangely enough, by the time I'd rolled to where the wind sock was, it
had dropped back down to nearly nothing. I filled the tank up at the
pumps (all the autogas here is now an ethanol blend, alas) and noted
that the wind was mostly light...with some strange little occasional
gusts directly across the runway.

We get dust devils here occasionally, though March is a bit early for
them. What really got me on this one, though, was the sound of the
whole thing... the fact that the wind gust was so loud that I could
hear it above the sound of the engine.